The Collaborative International Dictionary of English v.0.48:

Fleer \Fleer\, v. t.
   To mock; to flout at. --Beau. & Fl.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fleer \Fleer\, n.
   1. A word or look of derision or mockery.
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            And mark the fleers, the gibes, and notable scorn.
                                                  --Shak.
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   2. A grin of civility; a leer. [Obs.]
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            A sly, treacherous fleer on the face of deceivers.
                                                  --South.
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The Collaborative International Dictionary of English v.0.48:

fleer \fle"er\ (fl[=e]"[~e]r), n.
   One who flees. --Ld. Berners.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

fleer \fleer\ (fl[=e]r), [imp. & p. p. fleered (fl[=e]rd); p.
   pr. & vb. n. fleering.] [OE. flerien; cf. Scot. fleyr,
   Norw. flira to titter, giggle, laugh at nothing, MHG. vlerre,
   vlarre, a wide wound.]
   1. To make a wry face in contempt, or to grin in scorn; to
      deride; to sneer; to mock; to gibe; as, to fleer and
      flout.
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            To fleer and scorn at our solemnity.  --Shak.
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   2. To grin with an air of civility; to leer. [Obs.]
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            Grinning and fleering as though they went to a bear
            baiting.                              --Latimer.
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WordNet (r) 3.0 (2006):

fleer
    n 1: someone who flees from an uncongenial situation; "fugitives
         from the sweatshops" [syn: fugitive, runaway, fleer]
    2: contempt expressed by mockery in looks or words
    v 1: to smirk contemptuously

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "fleer":
   Parthian shot, affront, back answer, barrack, be merry with,
   call names, caustic remark, chaff, comeback, crack, crack a joke,
   crack wise, cut, cut at, cutting remark, dig, dig at, dishonor,
   disoblige, dump, dump on, fleer at, flout, foolery, fun, gibe,
   gibe at, gibing retort, gird, give offense to, grin, humiliate,
   hurl a brickbat, insult, jab, jab at, jape, jeer, jeer at, jest,
   jibe at, joke, josh, kid, kid around, leer, leg-pull, make a funny,
   make fun, make fun of, mock, offend, outrage, parting shot,
   play on words, poke fun at, pooh, pooh-pooh, pun, put down,
   put-down, put-on, quip, rail at, rally, rank out, revile, ridicule,
   rude reproach, sardonic grin, scintillate, scoff, scoff at,
   scornful laugh, scout, scurrility, short answer, slam, slap,
   slap at, smile, smirk, sneer, sneer at, snicker, snigger, snort,
   sparkle, swipe, taunt, treat with indignity, twit, utter a mot,
   verbal thrust, wisecrack